Develop Bugs

[Kernel] Flykernel-13 "Back from the Grave"

FlyKernel is an overclockable kernel for the Hero GSM, aimed to improve stability, battery life and performance (generally in that order).
The Hero GSM now also has a newer .35 kernel "Las Venturas" you should also check that one out. At the time of writing these lines, the newest version of Las Venturax is found on the second post of the above thread (my post ) - you should check which post is more up-to-date on that thread.
Download and instructions are on this post.
FAQ and advanced subjects are on the second post.
Change log and previous versions are on the third post.
WARNING: Please make sure to have an up-to-date backup before you flash this kernel!
FlyKernel-13 (#253)
FlyKernel 13 - Desean
FlyKernel 13 - Mediafire
FlyKernel 13 - Multiupload
This is a post-LasVenturas update for FlyKernel, after quite some time without any updates.
Although I currently have a bit of a personal preference for Las Venturas, I believe that it is even better to have two excellent kernels for the hero (internally totally different ), so that the users can choose whichever works best for them. Possibly, on some of the older ROMs this kernel might work better. This should also help isolate kernel issues vs. ROM issues.
SmartassV2 (informal description and comparison with the first smartass)
SmartassV2 is a governor (controls the frequency of the CPU at each give moment) which like the first smartass is generally based on the implementation of interactive with some major changes and the addition of a built in sleep profile (behaves a bit differently when screen is off vs. on).
The smartassV2 improves the very naive scheme which the first smartass had: The first smartass (with the values I set for the hero), would cap the max frequency at 352Mhz for sleep and when screen is on, would do the opposite and keep the frequency at 518Mhz or above. For sleep this was very effective but a bit crude and unclean, and there could be some cases where you would need processing power even when screen is off (something is updating and music is playing and etc.). For screen on, smartass1 was too quick to jump to the max available frequency and again would never go below the 518Mhz, so in a nutshell its was using "too high" frequencies.
SmartassV2, introduce (internally) an "ideal" frequency which is the frequency we are "aiming" for, in some sense. The way I see it is that the "ideal" frequency is a hint to the governor what is a good balance between performance and battery life. Now when screen is on, I set (on the hero) the ideal frequency to 518Mhz which will ensure nice responsiveness but limit unnecessary use of higher frequencies when they are not needed. When screen is off, I set the ideal frequency to 352Mhz (0 will disable the screen state tracking all together). From my testing this will "convince" the governor to spend most of the its time during sleep at the lowest available frequencies. Note, that both during sleep and when awake the entire frequency range (as defined by the "user" - i.e. selected with SetCPU) is used by smartassV2. For example, when the CPU is loaded heavily, the highest available frequency will be used regardless if screen is on or off.
Boot OC and optional tweaks
Optionally, you can rename the update file before you flash to change bootup frequencies and other options.
If you don't rename the file and flash "FlyKernel-13.zip" you will get the default tweaks and the min/max frequencies will remain as they where before.
For example, to set the max/min frequencies on boot to 614/176, rename "FlyKernel-13.zip" to "FlyKernel-13-M614-m176.zip".
Supported "flags" are:
Notice, all flags are case sensitive.
-MXXX - set max frequency to XXX
-mYYY - set min frequency to YYY
Supported max frequencies:
518 576 614 633 652 672 691 710 729 748
Supported min frequencies:
19 176 264 352 518 576 614 633 652 672 691 710 729 748
Default behavior, if these flags aren't given, is not to change your current settings.
For frequency recommendations and more info see FAQ #5.
Technical details: max/min frequencies are set in the kernel's ramdisk init.hero.rc file. Previous settings will be replaced. Furthermore, if one of your init.d script sets the max/min frequencies, these lines will be removed.
If you have SetCPU or other program changing the speed at boot, their change will take effect and overwrite this setting as soon as the ROM completes to boot.
-nologo - Don't show boot animation.
-logo - Show boot animation.
Default behaviour, if no flag is given, is not to change your current settings.
-noatime - Mount all partitions with -noatime to improve IO.
-atime - Mount no partition with -noatime.
Assuming, your ROM did not mount any partition with noatime, then the -atime option should undo the -noatime option perfectly. Unfortunately, it seems some ROMs (i.e. VR12) mount only some of the partitions with -noatime. It seems that in some cases, changing the noatime configuration causes boot problems.
Therefore, I highly recommend you make a backup before trying the -noatime flag - this is the only full proof way to go back if it messes something up.
Notice, this does not effect the ext partition as it is not mounted in the ramdisk init.rc. As far as I know, all ROMs mount the ext partition with noatime.
-notweak
By default, the updater will remove scheduler tweaks which exists in the ramdisk init.rc script, in order for the scheduler default compiled into the kernel to apply. This flag will disable this behavior.
More techinical information for developers about the smart update package has been updated in my github wiki.
Limitations and known bugs:
- This kernel will not make you coffee (I hope)!
Integrating kernel in a custom ROM (for ROM developers)
You can use my from above:
http://floyo.desean.net/FlyKernel-13-Floyo.zip
This file has a regular boot.img with a ramdisk compatible with Floyo 1.4, boots at 576/352 (smartassV2) and has all the kernel modules unpacked.
If you need to edit the ramdisk, you can either unpack the above boot.img as explained here. Or you can get the kernel binary file from my smart update package, under tmp/flykernel/kernel. The kernel modules are package in the smart update package under tmp/flykernel/syslibs.tar.
Kernel Sources
My sources with all my updates and changes are found on github:
http://github.com/erasmux/hero-2.6.29-flykernel
Use hero_defconfig for the regular version and hero-bfs_defconfig for the BFS version.
See the wiki for more information about building the kernel and more.
Please feel free to contact me regarding my sources and kernel development.
Using my Kernel Sources
Feel free to use my kernel sources, fully or partially in any (legal) way you see fit.
If you modify the sources, I urge you to share your changes with the community (as GPL obliges you to do), preferably using github. You can fork my sources on github, and this will make it easier for you to grab new changes from me and also allow you to fill pull requests so I can pull your changes back to my kernel.
GPL
Yes I am GPL complaint, all is included inside the sources, including the GPL license itself.
Thanks
Huge thanks to Desean for giving me file hosting that makes my life easier
Many thanks to all the Kernel/ROM developers here, especially those with open source kernels on github - LoxK, Cyanogen, Ninpo, Radu and especially Decad3nce.
Big thanks to all those who helped test the pre versions and reported bugs, specifically also to my long time testers (moonshield and floomat)
Donations are always welcome and accepted but are in no way required.

FAQ and Advanced Subjects
FAQ
0. When reporting a problem, do I need to include the ROM and exact kernel version I am using?
YES!
1. How do I flash the kernel update file?
You flash it from recovery, like any other custom ROM. If you are not familiar with recovery and/or haven't rooted your phone, start here.
2. Do I need to wipe anything when installing the kernel?
No you don't need to do any wipes. Just install the kernel through recovery and reboot
3. The update from recovery failed with errors/warning?
Please, in the same recovery session which you tried to apply the update and failed, select the "Move recovery.log to SD" from the "Other" menu and post in this thread with the recovery.log attached (for example in a .zip file).
4. After flashing the kernel my ROM does not boot
A logcat of the boot process might help me understand the problem. Using adb you can generate one with the following command and attach it to your report:
Code:
adb logcat > logcat.txt
You need to run this command relatively close to the start of the boot. Close the window after the phone is stuck for few minutes (say 2 mins with no change should do). You can start by running "adb logcat" and seeing if you get any output at all. If so, reboot once more and run the above command from the start of the boot (approximately).
Please also clearly state which ROM you are using and which kernel did work for you (which one did you use before).
To recover from such a scenario, boot into recovery and restore a backup of your working state. If you do not have a backup, and its the kernel fault, flashing your old kernel should solve the problem.
5. What min/max frequencies should I choose?
The short answer: min 176, max 614, if you have wake up issues up the min speed to 264 and then to 352.
To play with the speeds I suggest you install SetCPU (or similar app), so you can view and change your settings interactively. To change it permanently from the bootup see instructions on first post. You also use options like "Set on boot" in SetCPU if you prefer that.
The long answer:
The max frequency will effect the speed and responsiveness of your phone when screen is on. Note, that any speed above 528Mhz is above the specification of the manufacturer, hence is overclocking and could, in theory, shorten the life of your device. At high enough frequencies all devices will stop functioning, the exact threshold depends on your luck with your specific device. From my experience and knowledge, running at stable frequencies (or say one or two steps down to be on the safe side), should not harm your device - of course all overclocking is done at your sole responsibility.
As far as I know, almost all device can handle 652Mhz, most can reach the 691/710 area and some can even reach higher than the 748Mhz cap of this kernel. To find out which speed your phone supports, use SetCPU (or similar app), start from 614 for example and up the speed one tick a time. Don't select "Set on boot". At each step play with the phone a minute or two. If the phone gets stuck, reboot it (take out battery if necessary) and go one tick down.
Additionally, note the higher your max frequency the higher the battery drain will be when the screen is on. It is true that the display, data, wifi, gps, etc. should drain much more than the cpu. Still, I recommend staying in the sane frequencies range, no more than say 691Mhz (even if you phone can handle it).
Finally the min speed will effect standby battery life (when screen is off). From my experience there is a difference in battery life between 19Mhz and 352Mhz min frequencies but it is relatively small (much less than I expected). 19Mhz is not stable for me, almost stable, but over a period of weeks you will probably experience weird and possibly very rare instabilities. For me this was the when playing music with screen off the phone got stuck at 19Mhz (very hard to find this out), and became totally unresponsive until I rebooted it. Therefore, I recommend starting from 176Mhz, and if you have wakeup issues to bring it up. With 352Mhz you should have no wake up issues at all.
6. I am having wakeup issues (such as unresponsiveness to wakeup, weird coloring after wakeup, screen inversion, caller id not working on wakeup)
Up the min speed to 264 and then to 352. With a min frequency of 352 you should not have any wake issues.
See the FAQ #5 above for more information.
7. I am experiencing bad battery life with FlyKernel
First, please make sure to reboot the ROM at least one time after you flash the kernel. There have been reports that ROM/kernels behave badly on the first boot.
Personally, I do not do battery calibration, but if it makes you happy go for it. I do recommend at least charging the battery overnight, or a couple of hours after it has reached 100% to be sure it is full. Then use it, your regular usage for a few days and only then judge the battery life.
The battery percent indicator, over short periods of time seems extremely inaccurate and its very hard to reach any correct conclusions based on it.
If you do want to report bad battery life, please state your settings (kernel version, min/max speeds, governor, etc.), over which period you have been testing the battery, under what usage, what is the battery life you are used to having with which kernel and what is the battery life you are experiencing now.
Note, that roughly speaking, I lose less than 1%/hour when screen is off (wifi, data, gps, etc. also off), and about 10%/hours when just screen is on but phone does nothing at all (again wifi, gps, etc. off). About 20%+/hour when stressing my phone (although I have no data plan so can't test that). I am using the latest FlyKernel @ smartass 614/176.
8. What size should I give the swap partition?
short answer: 0.
long answer: I do not recommend using swap on the hero, hence 0. If you have a very fast SD card, and want to try it, give it say 64Mb. Note that I know of no ROM for the hero which activates swap automatically - you'll need to add a init.d script or something to activate it (see a bit more info here). Let me know if you find a scenario where the swap gives substantial improvement over no swap.
Finally note that FlyKernel versions before 12 do not support swap.
9. Should I use ext2, ext3 or ext4 for my ext partition?
Short answer: ext4. Note that FlyKernel versions before 12 did not support ext4, ext3 is supported since version 10.
Long answer:
Previously, I was under the impression that a journaling file system is a very bad idea for flashable storage. I still think its not ideal but better than the other alternative:
I have been using dual booting, placing an entire development ROM on an ext2/4 partition and using it for development. And when using ext2 it would get errors almost every boot and every couple of days get corrupted to the point I needed to manually restore damaged files to get it working....
It seems that if you only use it for app2sd, there are very infrequent changes to this volume (only when you install a new app), hence it does not get corrupted. But this also means that ext4, in this scenario, will not pay much overhead because there are very few changes. And in the case there are many changes, if I have to choose between a slightly shorter SD life with ext4 (and then I can finally get a faster one ) or risking my data getting corrupted on a daily basis with ext2 - I prefer the first (ext4).
Questions 10-13 are now obsolete with smartassV2 - see the first post for details about it
10. Do I need a SetCPU (or similar) screen off profile with smartass?
No, smartass automatically limits the screen on frequency to >= 518Mhz to ensure responsiveness, and screen off frequency to <= 352Mhz to keep standby battery life under control. Much like HTC's perfllock, it does this at the kernel level so it is much better than app level screen off profiles.
11. Using smartass the CPU frequency does not drop below 518Mhz (with screen on)
Intentional to ensure responsiveness. From my testing, when screen is on battery drain difference of speeds < 518Mhz is not significant relative to the drain by the screen itself.
12. Using smartass the CPU frequency does go above 352Mhz (with screen off)
Intentional to keep standby battery life under control.
13. Using smartass the CPU frequency is always at its max (or always at 352Mhz when screen is off)
See "Monitoring the CPU frequency" in the "Advanced subjects".
14. I am experiencing spontaneous reboots
Please post, in this thread, with as much detail as possible about the problem.
Please also attach the last_kmsg, which you can get from example using:
Code:
adb pull /proc/last_kmsg
15. What happend to the BFS version?
With the FlyKernel-12 scheduler tweaks (CFS scheduler), it surpasses the BFS version in every way. I tried to compile a BFS from the FlyKernel-12 code but even in neocore, in which the BFS was always much better, the new tweaked CFS leaves the BFS in the dust. Hence, I see no reason to continue and build/support a BFS version. The hero-bfs_defconfig is still up to date in my sources if anyone wants to build it themselves.
*. I am experiencing an issue not covered in the FAQ which I believe is kernel related
Please post, in this thread, with as much detail as possible about the problem.
Please also detail why you believe this kernel related. The best "proof" that it is the kernel's fault, is to flash back your old kernel and verify the problem is solved, then reflash the new kernel and verify the problem reappears. In any case please detail the kernel and version(s) on which your are experiencing the problem and those on which you do not.
Advanced Subjects
* Monitoring the CPU frequency
Will rewrite this more clearly. In the meantime:
http://forum.xda-developers.com/showpost.php?p=9925116&postcount=903
http://forum.xda-developers.com/showpost.php?p=9929325&postcount=919 <-- Mainly this one!!!
http://forum.xda-developers.com/showpost.php?p=9989996&postcount=970
http://forum.xda-developers.com/showpost.php?p=10010110&postcount=990

Change log and previous versions
FlyKernel-13
- Scheduler tweaks: use the scheduler settings that worked well on flykernel-11c and 12pre6 (tweaked them very very little), responsiveness should now be better than on the FlyKernel-12 release
- Backported the new smartassV2 - now the default
- Added interactiveX governor also
- A few config changes and compiler optimizations
FlyKernel 12a (mediafire)
- Fix wake up issues with new scheduler tweaks
- Smart update script: make noatime tweak option to (hopefully) solve boot problems
FlyKernel 12
- Smart update script
- Optimized scheduler parameters
- Fix Usb mass storage after usb tethering (at least on CM ROMs)
FlyKernel-12pre6
- Align ext2/3/4 config options
- Merge small fixes to lowmemorykiller module.
FlyKernel-12pre5
- Backport of smd rpcrouter to avs333 request.
FlyKernel-12pre4
- Partial fix for the lockscreen flickering when locked/unlocked rapidly (with smartass).
- Very small tweak to other smartass parameters.
FlyKernel-12pre3
- Fixed frequency table according to Radu's comments. Frequencies which are not on PLL2 have been removed!
- Tweaked smartass to spend more time at the lower frequencies to improve battery life. Also smartass's allergy to 19Mhz has been cured!
- Some configuration tweaks, mostly sleep related.
- 528Mhz frequency does not work well with OC, so it has been replaced with 518Mhz which does work fine.
FlyKernel-12pre2
FlyKernel-12pre2 optimized for CM based ROMs (default speed 576/352)
- Added compcache support
- Added 19Mhz and 264Mhz frequencies
FlyKernel-12pre1
- Lower voltages of high frequencies (>= 528Mhz)
- Added ext4 support (I currently use it for dual booting)
- Interactive updated (does anyone find it better than smartass? in what scenario?)
- Smartass fixes and optimizations - should be more responsive now and battery life should (hopefully) still be excellent.
- Camera backport from .32 (12pre1-cam32)
FlyKernel-11c
FlyKernel-11c #66 (Generic)
FlyKernel-11c-BFS #67 (Generic)
- Smartass: now wakeups up from sleep first at 528Mhz (no OC), to hopefully help with wake up issues.
- Bunch of fixes/optimization from CM espresso kernel and from Decad3nce (see github)
- BFS version
"Optimized Kernel Packages" (only for CM6 based ROMs: Floyo, Elelinux, Froyd):
Find the appropriate kernel for you by its name in the FlyKernel-11c directory
The naming conversion is:
flykernel-11c-CM-<min>-<max>.zip (with boot animation)
flykernel-11c-CM-<min>-<max>-nologo.zip (no boot animation)
flykernel-11c-BFS-... (BFS version)
FlyKernel-11
- New smartass governor (see technical detail below). Previous governors still supported.
- Added IPv6 (only for Google Googles?!)
- Fixes camera freezing CM6-based ROMs (thanks Ninpo for a "code cleanup" which fixed this )
- Fixes detection of USB connection during boot on CM6-based ROMs.
- Various squash-sets imported (see github)
- NORMALIZED_SLEEPER disabled.
FlyKernel-10a (rapidshare megaupload)
- Optimize some sleep/idle code (thanks to ninpo)
- Add module for IP header compression - hopefully this helps google apps (inspired by ninpo).
FlyKernel-10a-BFS (rapidshare megaupload)
- BFS version of 10a.
- Whats is BFS? see wikipedia and more details here.
FlyKernel-10
- Fixes for Froyo ROMs (FroydVillain and Elelinux)
- Added some more modules inside the kernel (notably using VPN should now work). I am now more aligned with the modules included in other kernels (well mainly ninpo's kernels), so hopefully you should not run into any missing modules.
I even added support for ext3.
- Generic update for all ROMs.
Flykernel-09:
FlyKernel-09 for VR12,RCMix,ChoclateEclair,Modaco and SuperHero
FlyKernel-09 for Kimera and Sensehero
FlyKernel-09 for MMod 1.2.3
FlyKernel-09 for FroydVillain and elelinux - Beware there are problems with 09 and Froyo ROMs.
FlyKernel-09 for CM6
- Added the excellent minmax governor.
- Removed interactive as it does not behave well at all - just use minmax
- added version which supports the 288M data partition - removed now since MAX appears to be fading out - just use dalvik2SD instead.
FlyKernel-08
FlyKernel-08 for Froyo and ASOP
Added Mike Chan's interactive governor, adaptation to Hero by Nadlabak and Ninpo. Added some tweaks of my own - now works well also with big frequency table.
Tweaked conservative governor for better performance.
Fixed/cleaned kernel co/nfig and modules - among other things iptables should work fine now.
Bigger frequency table.
FlyKernel-05 (BFS)
BFS version of the FlyKernel-04
FlyKernel-04
Based on HTC 2.6.29 official kernel source.
Includes patchset 2.6.29.6 and various fixes
Boot OC - Only for Sense based ROMs (The smart update script added in FlyKernel-12 provides a cleaner and better solution for all ROMs)
Boots very quickly by setting the OC speed right from the start. Also sets the original HTC boot animation which is quicker for most ROMs. Finally, replaces the 09zipalign with 09betterzipalign (again thanks ninpo).
Please have a backup before you try this, as there is no other easy way to undo this.
Select the update file according to the speed your phone can handle:
boot @ 653/160: http://www.multiupload.com/5RAXNJ7AWY (rapidshare megaupload)
boot @ 672/160: http://www.multiupload.com/RRQ0HYI8O8 (rapidshare megaupload)
boot @ 691/160: http://www.multiupload.com/20AJV7FLQI (rapidshare megaupload)
boot @ 710/160: http://www.multiupload.com/WHROUYNGQ6 (rapidshare megaupload)
Theoretically, this should now work on any ROM and any OC kernel. I have tested the 691 update on VR12 and Froyd 1.4 with my kernel and it works fine. Above files (now with "_" at end of name) updated to also work on ChocolateEclair and hopefully other ROMs on 31/8.
Note that in my recent kernel versions the lowest frequency is 176, so it will boot with a min frequency of 176.

cool.. will try. like the idea of overclocking before boot

can you post a diff file of what you modified?

diffs of which change?
there are a lot of changes and fixes, which range from fixes by me in the source code, to just copying/applying files from others.
I think it would be better to keep this thread open for issues and questions about the usage of these fixes. Still I will be more than happy to share anything I have done - please contact me with the exact change you are interested, either by PM or open a new thread if you think it is of general interest for developers.

There are literaly dozens of different kernels floating arround, all of which are always "brand new super fast ultra optimized". From a user perspective it's hard to tell which one is the best. I think this community needs more openness in the developpement. I think it would be a good habit if developpers posted their diff files (of everything) instead of just saying that they made "optimizations".
thanks for your work

zorxd said:
There are literaly dozens of different kernels floating arround, all of which are always "brand new super fast ultra optimized". From a user perspective it's hard to tell which one is the best. I think this community needs more openness in the developpement. I think it would be a good habit if developpers posted their diff files (of everything) instead of just saying that they made "optimizations".
thanks for your work
Click to expand...
Click to collapse
Trying it out might help in deciding which is the best for you. There is no such thing as an absolute best, sorry. To each his needs and his preferences. I also included a convenient undo update script which restores the original kernel.
Personally, I am not aware of any other kernels for the VillainROM (except the original one by ninpo) and for me my kernel works better. Additionally, I have gotten very good feedbacks for my kernel and fixes on iandroid (using HebVillain which is very tightly based on VR12). So I thought others here might want to try it and maybe would also like it. Please also feel free to bash it, but please try it first and then reply with comments which I can relate too.
Finally, I am all for complete openness: If you are really interested in the kernel sources, you can find them along with all my changes here which could be of great to help to you especially if you want to compile the hero kernel yourself. In such a case I would recommend starting from here. The biggest other change is the RTL fix, for which you find the diffs here (it is verses the eclair branch of the android source code). As for the other files & changes I did, I have tried to detail as much as possible in my original post.
Feel free to contact me (also by PM) if you want more info or help.

I just installed your Kernel and the Boot Optimization and brother my phone is flying!!!! GREAT JOB!!!
100% recommended flash for your VR12
THANKS!!!

yep!
all great! you are the MAN =)

good work erasmux, does it work with Arabic language with Arabic fonts installed ? I mean connected letters
Thanks a lot

I hope it does. I don't use Arabic, but if there are problems, report them and I'll do my best to fix them.

Good job erasmux!

Problems for me.....
Installed Kernel & Optimization and Boot time optimization
Made all my icons go to pot,
"problem loading gadget" on powerbar,
"problem loading gadget" on Battery Meter Widget
Game Icons, CoPilot live, System Widget all showing default app icon.
Lost a WHOLE LOAD of installed apps, simply not there listed any longer. So many gone I can't recall what I have lost.
Tried the undo file Original VR12 Kernel:
Got my apps back but still probs with some widgets, boot screen remained the HTC one (didn't revert to the villian screen)

First, I have fixed the kernel restore file in the original post to also restore the original villain boot animation, note that the new file is called: V12-RestoreKernel_.zip (with additional _ at end)
Thanks, for the remark.
Regarding the apps, that is very weird. Did you get these "problem loading gadget" on the screen or where? A logcat from the start of the boot would be very helpful (although I can understand if you don't want to flash it again just to help me debug...).
Regarding the widgets (when the apps do appear) ,try clearing the HTC Sense data (unfortunately this will reset your desktop but it should restore your widgets and its better than having to reinstall everything).

I'll have to have a go later.. tied up at the mo..
Prob loading gadget appeared on the screen (still does).
Will try clearing sense and post back later.
EDIT: Clearing Sense worked. Thanks.

made battery callibration (http://www.villainrom.co.uk/viewtopic.php?f=97&t=1789&start=20#p19769).. full charge (~17:15).. after 5 hours using phone.. 5-7 calls (1-5min each), 30 min wifi and playing =) and now ( 22:40) 99% battery!!! blja, im very happy!!!!!!!!!!
cpu always 245-576mhz
only like with original VR12 kernel after few hours of use at 576mhz linpack score down from 2.5 to 1.8 , but after installed autokiller ( preset 60mb) it's always 2.45-2.57
now i think VR12 the best!
Thank you one more time! will write back tomorrow eve =)

is this included stuff really usefull or it can be disabled?
ipv6 (lot of different options)
LZO and ARC4 crypto stuff
extra PPP stuff (MPPE, PPPOLAC, PPOPNS)
DSCP and TCPOPTSTRIP
INET_TUNNEL
XFRM_IPCOMP
CPU_FREQ_GOV_CONSERVATIVE
the /proc/config.gz (kernel .config support)
Also, I noticed that the device boot with mem=64M. Does it mean that the rest of the RAM isn't used?

AFAIK the only way to change this is to recompile the kernel.
Many of what you said I saw requests here on XDA that kernel developers add (there applications which use it). Please note that many of those modules do not automatically load and need to be manually loaded so they should not have any effect.
Others stuff, mainly the IPv6 stuff i doubt anyone uses - must have "inherited" it from the config i used as a base. I will look into it for future release if I can remove that stuff.
About the mem=64 I am not sure what that is, my phone is definitively using the full memory. I will also try to understand and possibly adjust that for future releases.
Thanks for the input.

An other question, is a kernel really tied to a specific ROM? I have VR12 right now so I could try it, but I was also thinking of upgrading to a 2.2 ROM.
About the modules, I think that most of the stuff that I noticed was compiled in (=y) and not as modules (=m). If they are only used by 1% of the users, I think it would be better to have them as modules and make sure that they don't load automatically at boot.
Also, do you know if it is better to have a small frequency table (with, let say, only 3 choices) to avoid excessive frequency switching?
Is the dalvik to SD trick included worth it for those of us with the original 2GB SD card?

Leankernel: ( JB4.2 - 7.1, JB4.3 - 8.3 - , KK 9.0 beta 11/25)

Ok guys i have got permission to bring over lean kernel and offer support for it on xda. I will keep this post up todate with all the most recent kernel updates and news. All credit goes to imoseyon as the original op and rootzwiki for original posting. I am posting this with full permission and support from imoseyon
Mod Type:: Kernel
Difficulty:: Very Easy
Mod Status:: Stable
Apply In:: CWM Recovery
Requires Root:: Yes
Exp builds are also up and includes a bunch of Android/OMAP updates not in stable.
SOURCE:
ICS
JB
This is a minimalistic Galaxy Nexus kernel. My philosophy is to keep the kernel as lean and stable as possible, at the same time to keep the kernel as modern and close to latest mainstream linux as possible. You will see that my kernels will lack some of the bells and whistles from other kernels.
sorry host4droid is still down. Mirrors:
kk4.4 LK 9.0 beta (use at ur own risk)
JB4.3 [ stable builds | exp builds ] [ change log | exp changes ]
JB4.2:Stable
Stock JRN84D kernel
Terminal Emulator not finding scripts? Read this post.
CHANGE LOG JB 4.2
FEATURES
Patched to latest in Linux 3.0.x branch.
All unnecessary kernel components removed to make kernel lean and fast!
OC to 1.65ghz. Boot speed is maxed at 1.2ghz within kernel (in addition to ramdisk) for stability.
User voltage control
InteractiveX V2 (screen-off hotplug of cpu1) added. Select it using setcpu if you want to use it.
Ramdisk tweaks (sysctl, vm, filesystem speed, etc.)
SWAP & zram (next generation compcache) support. Run "zram enable" in terminal.
init.d support in ramdisk.
lk.conf for basic kernel configuration.
HotplugX governor (Hotplug optimized and modified for screen-off suspend).
wakelock tweaks for wlan and lte modem
lkflash - script to flash latest versions of leanKernel from Terminal (type "su" without quotes, hit enter, then type "lkflash" without quotes and then hit enter)
checkv - voltage checking script (for custom undervolting) - detailed at bottom of this post.
checkt - script that displays 1) your current temp, 2) # of times you were throttled due to temp "recently", 3) CPU trim type, and 4) CPU silicon type, etc.
Fast USB charge (by chad0982) and "ffc" toggle script by me. (Open terminal, and type "ffc" without quotes then enter)
ColorControl from both CM9 and Ezekeel (compatible with all ROMs). Helpful posts: 1and 2.
TempControl - sysfs interface to control the CPU temp threshold. Read these two posts: 1 and 2.
Variable GPU OC - sysfs interface to select GPU max speed between 307MHz (stock), 384MHz and 512Mhz. The changes take effect immediately. Check FAQ for more info and how to use it.
Custom SR Tuning - override kernel default minimum voltage for SR calibration.
SoundControl
Gamma Control
ROW scheduler v4
DIRECTIONS
Uh.... flash the zip in clockworkmod.
Thanks to forum member maddler for providing file hosting
FAQ
How do i change voltage? - Use the latest version of setcpu, leantweaks, cputuner, or your ROM's built-in tools.
Do i need to wipe dalvik/cache? - in general there's no need, but it doesn't hurt so if you have time go ahead. Posted Image I don't wipe.
​Can we OC higher or add more frequency slots? - You can find the extra slots in my experimental versions.
​Will this work on GSM gnexus as well? - It should. I don't have a GSM phone to test so let me know if it stops working.
What is interactiveX V2? Read this post and thttp://rootzwiki.com/topic/13092-kernel-leankernel-minimalistic-kernel-120-123111/page__view__findpost__p__342571
Are you getting Screen-Off/Sleep-Of Death (SOD), general instability, or unusual battery drain?
Before you post here (especially if you're running the experimental version), try the following steps in order:
0) dude, disable screen-off profiles if you're running interactiveX.
1) If you're running the experimental version, do you have 180mhz/230mhz and/or 1.42ghz slots enabled? If so disable them both!
2) If the above doesn't help, do you have custom undervolting enabled? If so disable it! (keep in mind that the kernel is already undervolted by default).
3) If the above doesn't help, are you using interactiveX or hotplug governors? If so change to interactive.
4) If the above doesn't help then you should not be running the experimental version. Install the stable version and try both interactiveX and interactive without custom undervolting.
If you're still getting SOD with stable/interactive, report it here.
What about call-recording? - First the app needs to support Galaxy Nexus. Find out if it does and then find out from the author of the app what kernel changes are required and let me know.
Should i set up screen-off profile? - ICS kernels have built-in screen-off profile for all governors at 700mhz. So you don't need it unless you want to set it lower than 700mhz. In general there isn't a whole lot to gain by setting it lower.
Hotplug vs interactiveX? - Read this post. HotplugX vs interactiveX
What is zram and why do i need it?
zram basically takes a portion of your RAM (10% using my script) and turns it into a compressed swap device. So in layman's terms you're extending the size of your memory (potentially from ~700mb to close to 1000mb depending on the compression ratio).
To answer the 2nd question, no you don't really need it but if used properly (using custom LK zram script) it could help you in two different ways:
1) Android OS is based on Linux OS and the OS will try to use a growing portion of your RAM for file and inode caches and if you keep your phone up without rebooting after a while you may notice things getting a little sluggish. That's because the OS is not doing a good job in dropping the caches and freeing up memory for the apps.
2) more RAM and tweaked minfree (also handled by custom LK script) could potentially allow your apps to stay in memory longer (this may or may not be desirable based on your preference of course).
In conclusion, I'd say if you're curious it doesn't hurt to try. To revert, just type "zram disable".
What's the low-down on the GPU OC?
My kernel's GPU is now set to stock 307Mhz by default. You can adjust that by using Variable GPU OC (see a separate FAQ entry below).
When you go from say 307 to 512Mhz, you will not experience near double performance increase. Due to the factors outside the GPU module (ie. memory bandwidth limitation), you can't truly OC the GPU. In fact, most people can't tell the difference between 307, 384 and 512. Nenamark2 will roughly give you the following scores: 307/25fps, 384/28fps, and 512/31fps.
Some of you have seen the note from Colin, the Google kernel engineer, not to OC the GPU because using the OV_UV voltage slot will drain the battery. My kernel uses the same voltage for both OV and OV_UV slots. So there's no danger of battery drain there.
Why are the IO benchmark test scores lower than another kernel?
Some of the kernels out there have fsync disabled to increase benchmark scores. I believe that is unsafe and could cause data corruption. I do have hooks in my kernel to disable it but I don't use it.
In real world there will not be any user perceivable difference whether you have fsync enabled or disabled.
Is there a way to tune hotplug via sysfs?
yes. Advanced users only!
My phone doesn't seem to be deep-sleeping, what gives?
(assuming you checked in the right place like cpuspy) In terms of deep-sleep, there's not a whole lot going on in the kernel. It works or it doesn't - and I can assure you that I test every release (well almost every release) for deep-sleep before I release.
19 out of 20 times it's either 1) some sort of background process that's preventing your phone from going into deepsleep, or 2) something's misconfigured in your ROM, or both. Also connecting to USB will prevent phone from going into deepsleep.
I'm having unusual battery drain - help!
First of all, our gnex has very poor battery life while in active use. It's downright horrible while screen is on - screen is definitely the main culprit and there's not a whole lot I can do about that.
Custom undervolting can help or can hurt. This is mainly due to SmartReflex (class1.5) which auto-calibrates the ideal voltages for you. In fact, with SR you don't really need to use the custom undervolting feature for frequencies other than the 2 lowest. It does a great job calibrating higher frequencies. I personally don't touch it.
The "notrim" versions are an exception because I had to disable SR1.5 for the trim override to work. There's no auto-calibration going on there. Feel free to mess with custom undervolting on the notrim versions.
Now, if you've already accepted the horrible battery life while screen is on, but have questions about battery drain while idle - read the next question.
I'm having unusual battery drain while screen is off, or phone is sleeping - help!
First, let's find out if you're phone is going into deep-sleep. Install CPUSpy, unplug phone, turn off screen, and leave the phone alone for 5-10min. Turn the screen back on, launch CPUSpy, and see if you see an active entry for Deep Sleep. If so congratulations - read on.
If you've determined that your phone is not entering deepsleep by using the above method, read my entry above that says "My phone doesn't seem to be deep-sleeping". I've heard that removing SDM.apk helps as well as rebooting the phone. Also try turning your bluetooth on and off, and launching camera app and closing it.
If you've determined that your phone is entering deepsleep fine but still feel like battery drains, read the next question.
I'm having unusual battery drain while phone is in deep-sleep - help!
First make sure you are absolutely positive that deep sleep is working (read the previous question).
While on my kernel *and* connected to Wifi, you shouldn't drain more than 1% battery per hour *average* while in deep sleep (based on 5-8 hour continuous deep sleep). With wifi turned-off, my guess is probably no more than 1-3% per hour, depending on signal strength.
tip 1: If above is not happening for you, first charge the phone all the way and reboot. Let things settle a bit - give it a day or so. If you're using Battery Monitor Widget (which is not accurate for gnex), things should eventually settle between -2mA and -60mA per sample.
tip 2: Install BetterBatteryStats and look at which wakelocks dominate. Google search for names of the wakelocks to see how you can fix them.
tip 3: http://checkthis.com/d87t
If nothing seems to help, you can try the "notrim" version, but stick to speeds between 350 and 1350 (don't use OC slots). The notrim version has SR1.5 disabled which could help for those of you with drain issues on my other kernels.
What is tempcontrol and how do I use it?
First, read these two posts: 1 and 2.
Although tempcontrol was designed to be used with the experimental notrim builds because the cpu gets hotter in notrim frequencies, you can actually use tempcontrol to throttle lower frequencies. I haven't tried myself, but theoretically you can set your top speed at say 1.2Ghz and use tempcontrol to throttle at say 60C (instead of the stock value of 63C) resulting in slightly cooler phone. Theoretically.
What is SmartReflex?
SmartReflex performs continuous dynamic voltage scaling around the nominal operating point voltage according to silicon characteristics and operating conditions.
My stable and experimental builds will have SR Class 1.5 enabled by default.
You can disable SR via sysfs
How do I use Variable GPU OC?
You can use Lean Tweaks by Jake, or use the built-in "oc" script. Both leantweaks and my oc script will create an init.d script so the setting sticks at boot. My "checkt" script will also show the current GPU max speed. Note that 512MHz will probably not work for everyone.
307Mhz (stock) is set default by the kernel.
Open Terminal, and type for stock speed of 307Mhz: oc gpu 0
for 384MHz: oc gpu 1
for 512Mhz: oc gpu 2
What are the available sysfs options?
Check this post (thx byrong)
Which governor should I use on JB?
As usual I'd recommend trying all the governors and see which one works best for you. Stock JB, however, is optimized for interactive. The OS will automatically modify various interactive governor parameters on the fly while you're using the phone as part of "project butter". Namely, the following parameters are constantly adjusted by the OS: boostpulse, timer_rate, min_sample_time, hispeed_freq, go_hispeed_load, and above_hispeed_delay.
I hope this helps people if there is any other information you might want added just ask and i will do my best to come up with a comprehensive guide.
Donate to your favorite charity, or donate to imoseyon.

Did you ask Imoseyon before you posted this?

Thanks for bringing the thread over to XDA. Hopefully you got the necessary permissions, for the sake a peaceful thread. Its good to have most developments of the GNEX here and I finger tip away.
Sent from my Galaxy Nexus using xda premium

I've heard a lot about this kernel!

yes this is with his permisson

ajf64 said:
No i didn't ask him but i did put all due credits in it and it is in every other gnex forum but the sprint one all brought over by other people so if he has a problem with this he can feel free to pm me and i will get it removed i just figured it give us some easier access to his great kernel. In no way am i claiming this to be my work all support should be directed at the original thread op. I was just trying to make access to his kernel a bit easier for all xda users
Click to expand...
Click to collapse
That's all hunky dory but just doing things without asking the developer is just not right. Regardless if he has an issue or not. Its like you make something you work diligently on and then somebody just posts it somewhere else.
I dunno maybe its just me but its just common courtesy.
Sent From My Toro+ via SkyBlue Tapatalk

Thanks op.
#inb4close
#ReOpened
Sent from my Galaxy Nexus using Tapatalk 2

all fixed

ajf64 said:
well then sorry for posting it will a mod please delete this thread before it becomes a flame pit
Click to expand...
Click to collapse
Doesnt need to be deleted.. if just ask him if its alright.. thats fine enough

ÜBER™ said:
Doesnt need to be deleted.. if just ask him if its alright.. thats fine enough
Click to expand...
Click to collapse
Why do you always ruin the flaming? With your...good nature...and your rap music.

Thanks for linking. You can still ask dev for permission but I get what you're trying to do. I prefer xda since this is where I have gotten help with every phone since my nexus 1.
Sent from my Galaxy Nexus using XDA Premium HD app

Well i have gotten permission to post this from imoseyon and to keep this thread updated on xda sprint forums for him so it looks like we are all set he got back to me alot faster then i thought he would so every thing should be all good guys
and yes jayare313 i am so used to finding every thing i need on xda some times it s a pain having to check 3 or 4 sites to see if any of your mods for your rom are updated

Sorry. 3 issues here:
1) I need to verify permission from the developer and he needs to verify that he is going to support it here. If someone downloads it, flashes it, and somethings wrong.......who is going to give answers and support it? We have an active community who can help, sure, but the developer has to actively support it here. If he were ready to give support here, he would have posted it here already. And even then it would have to go in general unless he started the thread.
2) There is no source provided in the OP. Kernels must be GPL compliant and listed in the OP.
3) If you did not create it, do not post it in the development section.

Alrighty. Everything should be good now. I'll be keeping an eye out.
OP will be updated soon, with source and I've spoken to the developer.
Thank you guys.
---Jay--- From the GNex

Well, I will say I like having this thread here. So thanks to the op.
Sent from my Galaxy Nexus using Tapatalk 2

I will be updating the thread when i get home today and be offering any support you guys may need for this kernel

MichaelMcEntire said:
Well, I will say I like having this thread here. So thanks to the op.
Sent from my Galaxy Nexus using Tapatalk 2
Click to expand...
Click to collapse
I totally agree. Thanks to OP for the thread and imoseyon for the kernel
Sent from my Galaxy Nexus using xda premium

Np guys any time and if there is any thing i can help with just ask i plan to provide full support for this kernel. Also if there are things you wish to have added feel free to post them as well i have permission to compile my own versions of lean kernel with cherry picked features from his repository and to add features to it. I look forward to your feedback.

is 4.2 jb cm10 compatible

twoeleven99 said:
is 4.2 jb cm10 compatible
Click to expand...
Click to collapse
Yes
Sent from my Galaxy Nexus using xda app-developers app

[KERNEL][AOSP4.4/5.1/6.0/7.1] dkp - d2att - 2/4/18

Welcome to decimalman's kernel playground!​
As the name suggests, dkp is a hodgepodge of features and tweaks that I wanted to play with. It should get excellent battery life without feeling sluggish. It doesn't come with its own tuner app, so pick your favorite. Personally, I like Trickster MOD and Kernel Adiutor, so I go out of my way to make things work in them. Most other apps should work, too.
Features:
Overclocking up to 2.1 GHz, but you'll need to increase your voltages to get there (if you can get there at all)
Underclocking down to 54 MHz, with stability improvements
Undervolting compatible with most apps
Fast charge without unplugging first
Glorious animations for the notification and softkey LEDs
Well-integrated erandom means you don't need CrossBreeder or Seeder (recent AOSP builds use ISAAC instead)
freelunch and tierservative governors for optimal battery life without sacrificing responsiveness
Automatic mpdecision and auto-hotplug are only enabled when needed
Adjustable minimum voltage for stability on finicky processors
Optimized UKSM to free up some extra memory
Code optimizations for size and speed
Compiler optimizations (-O3, LTO, and more) because faster is better
Donors: Thanks, everyone! Your generosity is much appreciated. :good:
drpenguino, 0xScott, vmancini3 (twice! :good, Ch4m3l30n, rompnit, Mystique, ryandubbz, techdog, ElwOOd_CbGp, ScOULaris, ZipAddict
Remember:
Nandroid!
last_kmsg and/or logcat or it didn't happen.
Other kernels have their own threads or forums. Discuss them there.
Image dumps (settings, battery life, whatever) belong inside [HIDE][/HIDE] (that's HIDE, if you're on the mobile app) tags.
Be silly. We're here to have fun.
Installation:
Reboot to recovery. I recommend that one recovery...you know, the one that flashes zips? I forget what it's called.
Flash dkp. Optionally, rename and flash dkp-vmin-XXX.zip (see below).
Reboot.
Undervolting:
Undervolting on dkp is more complex than other kernels. Some processors get unstable at lower voltages, so (like the stock kernel) dkp keeps the processor voltage above 1150 mV by default. I refer to this limit as the minimum voltage. In order to undervolt, you'll need to lower the minimum voltage: if you use Trickster MOD or Kernel Adiutor, just disable "Override Minimum Voltage", otherwise rename dkp-vmin-XXX.zip to e.g. dkp-vmin-600.zip (which would apply a 600 mV minimum voltage) and flash it. If this causes instability (crashes, audio/video glitches, etc.), try using dkp-vmin-XXX.zip to apply a higher minimum voltage (somewhere between 950 and 1050 mV seems to work well for most people).
Downloads:
MediaFire:
All Downloads
dkp-vmin-XXX.zip
Solidfiles (Make sure you have an adblocker!):
All Downloads
dkp-vmin-XXX.zip
Source: I'm always happy to see my code used, so cherry-pick away. I'll even put together feature patches if you ask nicely.

Bugs:
Let me know.
Stable changelog:
3/3/13: Initial release for d2spr. Didn't get around to making threads for other carriers.
4/8/13 (3.0):
FauxSound support
Strip more useless stuff
A few bonus optimizations
4/8/13 (3.4):
Port everything except erandom from 3.0
Enhance cpufreq for easier configuration
4/24/13 (3.4):
Bugfixes: better support for tuner apps, fixed potential SOD bugs, automatic mpdecision fixups, etc.
Lots of CM/CAF/Linux updates
Working AssWax governor
Trinity colors support
sio, zen I/O schedulers
erandom is back!
Built with a super-fancy Linaro GCC 4.8.1-dev compiler toolchain for maximum -O3 goodness
Probably lots more, but there's hundreds of commits to sort through...
5/29/13 (3.4):
Bugfixes: better overclocking support, better hwrng support, etc.
Updates: new CM updates, Linux 3.4.47, updated FauxSound driver, added invisiblek's new panel colors interface
Automatic auto-hotplug
New optimizations, including link-time optimization and an updated GNU+Linaro GCC 4.8.1-dev toolchain
6/14/13 (3.4):
Bugfixes: fix several critical bugs in the 5/29 release.
9/7/13 (3.4):
Fixes for OC, UV, auto-hotplug.
A few new optimizations.
Synced up with CM.
9/20/13 (TW):
Ported everything from AOSP to TW.
9/20/13 (4.3):
Merged 4.3 from CM into the existing 4.2 code.
Current experimental branches:
Nothing interesting at the moment.

Goodies:
dkp doesn't come with its own splash screen. However, the dkp installer (i.e. the install zip) is smarter than you think, and can apply a custom splash screen for you. Here's how:
Create a folder on your internal storage named "dkp"
Copy a PNG image into the directory, and rename it "splash.png". Alternatively, copy an RLE image (i.e. from a flashable custom splash screen zip) and rename it "splash.rle". Ideally, the image should be roughly 1280x720 to begin with, since it won't be resized.
The image will be used as your splash screen whenever you flash dkp. Reflash to apply initially.
mikedavis120 has put together a how-to video that covers tweaking dkp for optimal battery life. If you're new to dkp, take a look! He also put together a zipped collection of apps that will come in handy while tuning dkp. It also includes a flashable zip, "dkp-debug_v1.zip". After flashing it, running
Code:
su
dkp
from a terminal emulator will collect lots of useful debug information that will make it much easier for me to track down the issue you're having. :good: mikedavis120 recommends installing SuperSU (included in the zip) instead of what's included in you ROM.
sysfs:
It's possible to adjust all the settings available in dkp without using apps. Because they show up as files, settings can be adjusted with file managers, terminal emulators, adb and initscripts. Here's the most interesting files inside sysfs:
/sys/devices/platform/mipi_samsung_oled.513/lcd/panel/panel_colors (not available on newer AOSP builds): display tint (0 = very red, 2 = default, 4 = trinity colors)
/sys/class/misc/gammacontrol (only available on newer AOSP builds): various color controls. See this post for details on enabling Trinity colors on builds that use these controls.
/sys/devices/system/cpu/cpu<N>/cpufreq/UV_mV_table: voltage table
/sys/devices/system/cpu/cpu<N>/cpufreq/scaling_...: scaling_governor is the governor, scaling_min_freq and scaling_max_freq are the minimum and maximum frequencies, scaling_available_governors and scaling_available_frequencies show the available governors and frequencies
/sys/kernel/dkp/force_fast_charge: fast charge
/sys/kernel/dkp/link_core_settings: when linked (the default), frequency settings and some governors are automatically copied to the other core
/sys/kernel/dkp/vmin: minimum processor voltage in mV
/sys/kernel/mm/uksm/run: activate UKSM
auto-hotplug tuners:
These show up in the governor settings for any governor that doesn't do its own hotplugging. They only take effect when using auto-hotplug, so you'll probably need to disable mpdecision in Trickster.
hotplug_intpulse: when set to 1, automatically turns core 2 on whenever the screen/buttons/whatever is pressed. Default is 0.
hotplug_sampling_periods: number of samples to use for average number of running tasks. Default is 15.
hotplug_sampling_rate: number of 'jiffies' (currently 1 jiffy = 10 ms) between each sample of running tasks. Default is 20 (0.2 sec).
hotplug_enable_one_threshold: the average number of running tasks required to turn core 2 on, multiplied by 100. Default is 125 (1.25 tasks on average).
hotplug_disable_one_threshold: the average number of running tasks required to keep core 2 on, multiplied by 100. Default is 250 (2.5 tasks on average).
freelunch/nanolunch tuners:
freelunch and nanolunch aren't materially based on other governors, so their configuration is quite different than other governors. There's lots of tuners, since I haven't really decided on an ideal tuning. I encourage experimentation! I'll explain a bit of how these governors work before actually listing the tuners.
Generally speaking, there are two modes: in "normal" mode, sampling is done occasionally and frequency is generally increased slowly; in "interactive" mode, sampling is done much more quickly, and frequency increases much more quickly. "Interactive" mode ends after several samples of very low usage. The idea of a "hispeed" frequency is used in lots of governors, and it refers to the frequency that the CPU will jump to when more CPU usage is needed; generally, it's a generous estimate of how much CPU will be needed. Here, the hispeed frequency is adjusted on-the-fly, increasing when more CPU is needed and gradually decreasing when the CPU is idle. In "interactive" mode, the hispeed frequency is kept fairly high so that everything will feel snappy.
Hotplugging is taken care of in the least complicated (and in my opinion, most reasonable) way possible: if core 1 is using lots of CPU, and there are several tasks running (in other words, if it's likely that core 2 will have something to do), core 2 is turned on; if either core isn't doing much except using power, core 2 is turned off.
sampling_rate: the usual
hotplug_up_cycles: number of consecutive heavily-loaded samples before core 2 is turned on
hotplug_down_cycles: number of consecutive lightly-loaded samples before core 2 is turned off
hotplug_up_load: number of running tasks required to bring core 2 online
hotplug_up_usage: number of used CPU cycles (in thousands per second) required to bring core 2 online
hotplug_down_usage: number of used CPU cycles (in thousands per second) required on both cores to keep core 2 online
overestimate_khz: number of CPU cycles to overshoot usage by in "normal" mode
hispeed_thresh: if CPU usage is within this many cycles (in thousands per second) of the maximum frequency, frequency will be increased to the hispeed frequency. Generally, hispeed is pretty low in "normal" mode, and fairly high in "interactive" mode.
hispeed_decrease: when the CPU is sitting idle, the hispeed frequency is decreased by this amount each sample (this isn't ideal, but it works)
interaction_hispeed: the initial hispeed frequency when switching to "interactive" mode
interaction_return_cycles: number of consecutive lightly-loaded samples before returning to "normal" mode
interaction_return_usage: number of used CPU cycles (in thousands per second) required to stay in "interactive" mode
interaction_panic (nanolunch only): when set to 1, allows aggressively jumping past the current hispeed frequency under some circumstances
interaction_sampling_rate/overestimate_khz: equivalent to the "normal" versions of the tuners, these take effect in "interactive" mode

Just loaded it on pa 3.15
Sent from my SAMSUNG-SGH-I747 using xda premium

It doesn't say that it has morfic colors, but looks like it does. Gonna give it a whirl
Sent from my SGH-I747 using xda app-developers app

rmead01 said:
It doesn't say that it has morfic colors, but looks like it does. Gonna give it a whirl
Sent from my SGH-I747 using xda app-developers app
Click to expand...
Click to collapse
It doesn't, but I'll merge it and put out a test build.

decimalman said:
It doesn't, but I'll merge it and put out a test build.
Click to expand...
Click to collapse
Is it possible they are left over from a previous kernel? Because I can def tell the difference usually and seems like it does.
Either way, advise when its updated. This governor seems solid so far.
Sent from my SGH-I747 using xda app-developers app

rmead01 said:
Is it possible they are left over from a previous kernel? Because I can def tell the difference usually and seems like it does.
Either way, advise when its updated. This governor seems solid so far.
Sent from my SGH-I747 using xda app-developers app
Click to expand...
Click to collapse
dkp is based off clean CM source, so it shouldn't have been merged already.
I've got test builds compiling now, and the 3.4 builds will be up shortly. Flashing the trinity-colors test build and this zip will enable trinity colors. You can toggle it with
Code:
su
echo X >/sys/class/mdnie/mdnie/trinity_colors
where X is 0 to disable or 1 to enable.
Edit: and sorry for taking so long to respond.
Edit 2: 3.4 builds are up. http://d-h.st/7Ae

Thnx for this kernel

decimalman said:
dkp is based off clean CM source, so it shouldn't have been merged already.
I've got test builds compiling now, and the 3.4 builds will be up shortly. Flashing the trinity-colors test build and this zip will enable trinity colors. You can toggle it with
Code:
su
echo X >/sys/class/mdnie/mdnie/trinity_colors
where X is 0 to disable or 1 to enable.
Edit: and sorry for taking so long to respond.
Edit 2: 3.4 builds are up. http://d-h.st/7Ae
Click to expand...
Click to collapse
Maybe I was just seeing things, had just watched jurassic park in 3d.
New "test" build flashed as well as the file to enable it. Thanks for the addition. It's very hard to go back to normal once you've been smurfed depending on your display.
Only issue i'm having ATM is the ability to change the voltage table. My phone doesn't handle undervolting as well and i run a minimum of 950 baseline, if not 975. One of my normal apps wasn't able to set the voltage at all. I'm trying to use performance control which I don't like. It crashes trying to set the voltage on boot but at least I can go in and manually set the values on boot and they stick.
One last question, since this is your kernel, what scheduler do you recommend pairs well to freelunch? What would you use for performance and what would you use for batt?

rmead01 said:
One last question, since this is your kernel, what scheduler do you recommend pairs well to freelunch? What would you use for performance and what would you use for batt?
Click to expand...
Click to collapse
+1 on these questions
Sent from my AT&T Samsung Galaxy S III

rmead01 said:
Only issue i'm having ATM is the ability to change the voltage table. My phone doesn't handle undervolting as well and i run a minimum of 950 baseline, if not 975. One of my normal apps wasn't able to set the voltage at all. I'm trying to use performance control which I don't like. It crashes trying to set the voltage on boot but at least I can go in and manually set the values on boot and they stick.
Click to expand...
Click to collapse
Answered my own problem. I installed trickster as mentioned in OP and all voltage settings stick no problem with no issues.

rmead01 said:
New "test" build flashed as well as the file to enable it. Thanks for the addition. It's very hard to go back to normal once you've been smurfed depending on your display.
Only issue i'm having ATM is the ability to change the voltage table. My phone doesn't handle undervolting as well and i run a minimum of 950 baseline, if not 975. One of my normal apps wasn't able to set the voltage at all. I'm trying to use performance control which I don't like. It crashes trying to set the voltage on boot but at least I can go in and manually set the values on boot and they stick.
One last question, since this is your kernel, what scheduler do you recommend pairs well to freelunch? What would you use for performance and what would you use for batt?
Click to expand...
Click to collapse
Personally, I don't like trinity colors, but I definitely understand the appeal. I merged this into 3.0 and 3.4, so it'll be standard from here on. I'll add a link to the enabler zip in the OP as well.
What app would you normally use? I'll try to support it, since I already provide several voltage interfaces. I didn't realize performance control was crashing (I'm not a fan either, so I only lightly tested). I recently installed Trickster and liked it, so I've been going out of my way to support it. It's also really easy to write support for, so that's a bonus for me.
As for schedulers, I'm not fussy. I've never exhaustively tested performance and battery life, so I don't have a preference and usually run noop or deadline. However, I've had nothing but bad results with ROW (phone never deep sleeps, and I haven't looked into why).

decimalman said:
Personally, I don't like trinity colors, but I definitely understand the appeal. I merged this in, so it'll be standard from here on. I'll add a link to the enabler zip in the OP as well.
What app would you normally use? I'll try to support it, since I already provide several voltage interfaces. I didn't realize performance control was crashing (I'm not a fan either, so I only lightly tested). I recently installed Trickster and liked it, so I've been going out of my way to support it. It's also really easy to write support for, so that's a bonus for me.
As for schedulers, I'm not fussy. I've never exhaustively tested performance and battery life, so I don't have a preference and usually run noop or deadline. However, I've had nothing but bad results with ROW (phone never deep sleeps, and I haven't looked into why).
Click to expand...
Click to collapse
good to know. Trickster mod works fine and you mention it in the OP and it's at no cost in the play store. I wouldn't worry.
I was using an app called kernel tuner because some others would only set 1 core to the governor and not both. I checked that trickster does indeed set both cores to freelunch so once that figured out I removed kernel tuner. Kernel Tuner also has the options for profiles which can be toggled in tasker for varies states. freelunch so far hasn't needed any changing so not worried about it at this point. just as an example, some governors would be better for screen on/off and tasker could switch these to edge out battery life.
The voltage app i was using is simply called voltage control. Kernel tuner doesn't do a nice job of voltage changes. But since trickster does both governor and voltage adjustments well. i'm using that with no problems now.
Thanks for the morfic, having a way to toggle it works well for people. it's as simple as a script so there's that.

rmead01 said:
good to know. Trickster mod works fine and you mention it in the OP and it's at no cost in the play store. I wouldn't worry.
I was using an app called kernel tuner because some others would only set 1 core to the governor and not both. I checked that trickster does indeed set both cores to freelunch so once that was made it was no problem. Kernel Tuner also has the options for profiles which can be toggled in tasker for varies states. freelunch so far hasn't needed any changing so not worried about it at this point.
The voltage app i was using is simply called voltage control. Kernel tuner doesn't do a nice job of voltage changes. But since trickster does both well, i'm using that with no problems now.
Thanks for the morfic, having a way to toggle it works well for people. it's as simple as a script so there's that.
Click to expand...
Click to collapse
I meant to test Voltage Control but Google wasn't letting me download anything. It's a common app, so I'll try to get it working regardless. Kernel Tuner doesn't currently work well with freelunch, and tends to hang when it's trying to read settings in the CPU screen. Otherwise, it's a nice app. I didn't realize it had Tasker support (I use Llama).
I've added a few extra bits to the cpufreq core, so governors that need to be set on both cores (like freelunch) will automatically apply to both cores regardless of what app is used. cpufreq will even enable and disable mpdecision depending on whether a hotplugging governor is running (though Trickster won't show that it's disabled).
I owe ktoonsez for the toggleable trinity colors. I slightly rewrote his patch, but it's still largely his code. It's my policy that anything that not all users will want should be optional and easily configurable.
Edit: I think I've got Voltage Control fixed. I should be able to get Kernel Tuner working without too much work. I haven't even looked into Performance Control yet.

decimalman said:
I meant to test Voltage Control but Google wasn't letting me download anything. It's a common app, so I'll try to get it working regardless. Kernel Tuner doesn't currently work well with freelunch, and tends to hang when it's trying to read settings in the CPU screen. Otherwise, it's a nice app. I didn't realize it had Tasker support (I use Llama).
I've added a few extra bits to the cpufreq core, so governors that need to be set on both cores (like freelunch) will automatically apply to both cores regardless of what app is used. cpufreq will even enable and disable mpdecision depending on whether a hotplugging governor is running (though Trickster won't show that it's disabled).
I owe ktoonsez for the toggleable trinity colors. I slightly rewrote his patch, but it's still largely his code. It's my policy that anything that not all users will want should be optional and easily configurable.
Click to expand...
Click to collapse
well good job so far. batt life has been top notch. minimal drain in use and my over night idle drain was only a few %. I have things setup to disable wifi when sleep and also turn off mobile data when wifi is connected. A bit over the top but every bit helps.
:good::highfive:

I know I've been grilling you today but...
Kind of curious what the new tunables do. I haven't touched anything since it's working so well but there is always that part of me that wonders what adjust parameters will do. Is there any kind of reference for this governor that could indicate that type of info?

Does your kernel support faux sound app?

stevehkim said:
Does your kernel support faux sound app?
Click to expand...
Click to collapse
Yes. 3.0 and 3.4 both have support.
As for tuneables, I've been meaning to post a writeup but haven't gotten around to it. You're not the first to ask about it.
Sent from my SPH-L710 using xda app-developers app

This is a fantastic Kernel! The battery life has been outstanding so far. Thank you for your amazing work!

[KERNEL][AOSP4.4/5.1/6.0/7.1] dkp - d2tmo - 2/4/18

Welcome to decimalman's kernel playground!​
As the name suggests, dkp is a hodgepodge of features and tweaks that I wanted to play with. It should get excellent battery life without feeling sluggish. It doesn't come with its own tuner app, so pick your favorite. Personally, I like Trickster MOD and Kernel Adiutor, so I go out of my way to make things work in them. Most other apps should work, too.
Features:
Overclocking up to 2.1 GHz, but you'll need to increase your voltages to get there (if you can get there at all)
Underclocking down to 54 MHz, with stability improvements
Undervolting compatible with most apps
Fast charge without unplugging first
Glorious animations for the notification and softkey LEDs
Well-integrated erandom means you don't need CrossBreeder or Seeder (recent AOSP builds use ISAAC instead)
freelunch and tierservative governors for optimal battery life without sacrificing responsiveness
Automatic mpdecision and auto-hotplug are only enabled when needed
Adjustable minimum voltage for stability on finicky processors
Optimized UKSM to free up some extra memory
Code optimizations for size and speed
Compiler optimizations (-O3, LTO, and more) because faster is better
Donors: Thanks, everyone! Your generosity is much appreciated. :good:
drpenguino, 0xScott, vmancini3 (twice! :good, Ch4m3l30n, rompnit, Mystique, ryandubbz, techdog, ElwOOd_CbGp, ScOULaris, ZipAddict
Remember:
Nandroid!
last_kmsg and/or logcat or it didn't happen.
Other kernels have their own threads or forums. Discuss them there.
Image dumps (settings, battery life, whatever) belong inside [HIDE][/HIDE] (that's HIDE, if you're on the mobile app) tags.
Be silly. We're here to have fun.
Installation:
Reboot to recovery. I recommend that one recovery...you know, the one that flashes zips? I forget what it's called.
Flash dkp. Optionally, rename and flash dkp-vmin-XXX.zip (see below).
Reboot.
Undervolting:
Undervolting on dkp is more complex than other kernels. Some processors get unstable at lower voltages, so (like the stock kernel) dkp keeps the processor voltage above 1150 mV by default. I refer to this limit as the minimum voltage. In order to undervolt, you'll need to lower the minimum voltage: if you use Trickster MOD or Kernel Adiutor, just disable "Override Minimum Voltage", otherwise rename dkp-vmin-XXX.zip to e.g. dkp-vmin-600.zip (which would apply a 600 mV minimum voltage) and flash it. If this causes instability (crashes, audio/video glitches, etc.), try using dkp-vmin-XXX.zip to apply a higher minimum voltage (somewhere between 950 and 1050 mV seems to work well for most people).
Downloads:
MediaFire:
All Downloads
dkp-vmin-XXX.zip
Solidfiles (Make sure you have an adblocker!):
All Downloads
dkp-vmin-XXX.zip
Source: I'm always happy to see my code used, so cherry-pick away. I'll even put together feature patches if you ask nicely.

Bugs:
Let me know.
Stable changelog:
3/3/13: Initial release for d2spr. Didn't get around to making threads for other carriers.
4/8/13 (3.0):
FauxSound support
Strip more useless stuff
A few bonus optimizations
4/8/13 (3.4):
Port everything except erandom from 3.0
Enhance cpufreq for easier configuration
4/24/13 (3.4):
Bugfixes: better support for tuner apps, fixed potential SOD bugs, automatic mpdecision fixups, etc.
Lots of CM/CAF/Linux updates
Working AssWax governor
Trinity colors support
sio, zen I/O schedulers
erandom is back!
Built with a super-fancy Linaro GCC 4.8.1-dev compiler toolchain for maximum -O3 goodness
Probably lots more, but there's hundreds of commits to sort through...
5/29/13 (3.4):
Bugfixes: better overclocking support, better hwrng support, etc.
Updates: new CM updates, Linux 3.4.47, updated FauxSound driver, added invisiblek's new panel colors interface
Automatic auto-hotplug
New optimizations, including link-time optimization and an updated GNU+Linaro GCC 4.8.1-dev toolchain
6/14/13 (3.4):
Bugfixes: fix several critical bugs in the 5/29 release.
9/7/13 (3.4):
Fixes for OC, UV, auto-hotplug.
A few new optimizations.
Synced up with CM.
9/20/13 (TW):
Ported everything from AOSP to TW.
9/20/13 (4.3):
Merged 4.3 from CM into the existing 4.2 code.
Current experimental branches:
Nothing interesting at the moment.

Goodies:
dkp doesn't come with its own splash screen. However, the dkp installer (i.e. the install zip) is smarter than you think, and can apply a custom splash screen for you. Here's how:
Create a folder on your internal storage named "dkp"
Copy a PNG image into the directory, and rename it "splash.png". Alternatively, copy an RLE image (i.e. from a flashable custom splash screen zip) and rename it "splash.rle". Ideally, the image should be roughly 1280x720 to begin with, since it won't be resized.
The image will be used as your splash screen whenever you flash dkp. Reflash to apply initially.
mikedavis120 has put together a how-to video that covers tweaking dkp for optimal battery life. If you're new to dkp, take a look! He also put together a zipped collection of apps that will come in handy while tuning dkp. It also includes a flashable zip, "dkp-debug_v1.zip". After flashing it, running
Code:
su
dkp
from a terminal emulator will collect lots of useful debug information that will make it much easier for me to track down the issue you're having. :good: mikedavis120 recommends installing SuperSU (included in the zip) instead of what's included in you ROM.
sysfs:
It's possible to adjust all the settings available in dkp without using apps. Because they show up as files, settings can be adjusted with file managers, terminal emulators, adb and initscripts. Here's the most interesting files inside sysfs:
/sys/devices/platform/mipi_samsung_oled.513/lcd/panel/panel_colors (not available on newer AOSP builds): display tint (0 = very red, 2 = default, 4 = trinity colors)
/sys/class/misc/gammacontrol (only available on newer AOSP builds): various color controls. See this post for details on enabling Trinity colors on builds that use these controls.
/sys/devices/system/cpu/cpu<N>/cpufreq/UV_mV_table: voltage table
/sys/devices/system/cpu/cpu<N>/cpufreq/scaling_...: scaling_governor is the governor, scaling_min_freq and scaling_max_freq are the minimum and maximum frequencies, scaling_available_governors and scaling_available_frequencies show the available governors and frequencies
/sys/kernel/dkp/force_fast_charge: fast charge
/sys/kernel/dkp/link_core_settings: when linked (the default), frequency settings and some governors are automatically copied to the other core
/sys/kernel/dkp/vmin: minimum processor voltage in mV
/sys/kernel/mm/uksm/run: activate UKSM
auto-hotplug tuners:
These show up in the governor settings for any governor that doesn't do its own hotplugging. They only take effect when using auto-hotplug, so you'll probably need to disable mpdecision in Trickster.
hotplug_intpulse: when set to 1, automatically turns core 2 on whenever the screen/buttons/whatever is pressed. Default is 0.
hotplug_sampling_periods: number of samples to use for average number of running tasks. Default is 15.
hotplug_sampling_rate: number of 'jiffies' (currently 1 jiffy = 10 ms) between each sample of running tasks. Default is 20 (0.2 sec).
hotplug_enable_one_threshold: the average number of running tasks required to turn core 2 on, multiplied by 100. Default is 125 (1.25 tasks on average).
hotplug_disable_one_threshold: the average number of running tasks required to keep core 2 on, multiplied by 100. Default is 250 (2.5 tasks on average).
freelunch/nanolunch tuners:
freelunch and nanolunch aren't materially based on other governors, so their configuration is quite different than other governors. There's lots of tuners, since I haven't really decided on an ideal tuning. I encourage experimentation! I'll explain a bit of how these governors work before actually listing the tuners.
Generally speaking, there are two modes: in "normal" mode, sampling is done occasionally and frequency is generally increased slowly; in "interactive" mode, sampling is done much more quickly, and frequency increases much more quickly. "Interactive" mode ends after several samples of very low usage. The idea of a "hispeed" frequency is used in lots of governors, and it refers to the frequency that the CPU will jump to when more CPU usage is needed; generally, it's a generous estimate of how much CPU will be needed. Here, the hispeed frequency is adjusted on-the-fly, increasing when more CPU is needed and gradually decreasing when the CPU is idle. In "interactive" mode, the hispeed frequency is kept fairly high so that everything will feel snappy.
Hotplugging is taken care of in the least complicated (and in my opinion, most reasonable) way possible: if core 1 is using lots of CPU, and there are several tasks running (in other words, if it's likely that core 2 will have something to do), core 2 is turned on; if either core isn't doing much except using power, core 2 is turned off.
sampling_rate: the usual
hotplug_up_cycles: number of consecutive heavily-loaded samples before core 2 is turned on
hotplug_down_cycles: number of consecutive lightly-loaded samples before core 2 is turned off
hotplug_up_load: number of running tasks required to bring core 2 online
hotplug_up_usage: number of used CPU cycles (in thousands per second) required to bring core 2 online
hotplug_down_usage: number of used CPU cycles (in thousands per second) required on both cores to keep core 2 online
overestimate_khz: number of CPU cycles to overshoot usage by in "normal" mode
hispeed_thresh: if CPU usage is within this many cycles (in thousands per second) of the maximum frequency, frequency will be increased to the hispeed frequency. Generally, hispeed is pretty low in "normal" mode, and fairly high in "interactive" mode.
hispeed_decrease: when the CPU is sitting idle, the hispeed frequency is decreased by this amount each sample (this isn't ideal, but it works)
interaction_hispeed: the initial hispeed frequency when switching to "interactive" mode
interaction_return_cycles: number of consecutive lightly-loaded samples before returning to "normal" mode
interaction_return_usage: number of used CPU cycles (in thousands per second) required to stay in "interactive" mode
interaction_panic (nanolunch only): when set to 1, allows aggressively jumping past the current hispeed frequency under some circumstances
interaction_sampling_rate/overestimate_khz: equivalent to the "normal" versions of the tuners, these take effect in "interactive" mode

Look promising

kruse1944 said:
Look promising
Click to expand...
Click to collapse
Wow you're quick!
Let me know how it works for you. Happy flashing!

Thanks for your work:good:

Is it just me or is the voltage table backwards, higher voltages for lower cpu speeds?
Sent from my SGH-T999 using xda app-developers app

Am I missing something? Where do I dl d2tmo?
Sent from my Wicked fast SGS3!

akapaul26 said:
Am I missing something? Where do I dl d2tmo?
Sent from my Wicked fast SGS3!
Click to expand...
Click to collapse
You download the att one. Works for tmo.
Sent from my SGH-T999 using Tapatalk 2

robertd0619 said:
You download the att one. Works for tmo.
Sent from my SGH-T999 using Tapatalk 2
Click to expand...
Click to collapse
Thanks for helping out. :good: I'll change the file name to be more obvious shortly.
darjama said:
Is it just me or is the voltage table backwards, higher voltages for lower cpu speeds?
Sent from my SGH-T999 using xda app-developers app
Click to expand...
Click to collapse
Bizarre. The tables are all correct and should display correctly, but your app is probably expecting a slightly different format. What app are you using? I'll try to figure out what's going on.

This kernel works great thanks I'm on pac rom. Thanks
aaaaaaaaahhhhhhhhhhhhhhh help me

decimalman said:
Thanks for helping out. :good: I'll change the file name to be more obvious shortly.
Bizarre. The tables are all correct and should display correctly, but your app is probably expecting a slightly different format. What app are you using? I'll try to figure out what's going on.
Click to expand...
Click to collapse
just took a look at your acpuclock tables, the first table uv to 1400000 but others don't match. nomal and fast should match up with one another from my experience. The multipliers seem good tho

ayysir said:
just took a look at your acpuclock tables, the first table uv to 1400000 but others don't match. nomal and fast should match up with one another from my experience. The multipliers seem good tho
Click to expand...
Click to collapse
The tables I'm using are the stock tables from CM & Samsung (obviously with extra frequencies added as well). I've deliberately kept the standard voltage setup (minimum voltage, different voltage tables for each PVS bin, etc.), although by default I disable the minimum voltage during boot.
On the other hand, at 2106 MHz, the PVS bin probably doesn't matter, and all three bins probably need the full 1.4 V. My processor undervolts nicely, so I don't have a good sense for what voltage is required when overclocking. If anyone provides me tables that work for them, I'll update the higher voltages.
LOL the multipliers should be fine except the ridiculous 2.5 GHz typo that should never have been committed.

decimalman said:
The tables I'm using are the stock tables from CM & Samsung (obviously with extra frequencies added as well). I've deliberately kept the standard voltage setup (minimum voltage, different voltage tables for each PVS bin, etc.), although by default I disable the minimum voltage during boot.
On the other hand, at 2106 MHz, the PVS bin probably doesn't matter, and all three bins probably need the full 1.4 V. My processor undervolts nicely, so I don't have a good sense for what voltage is required when overclocking. If anyone provides me tables that work for them, I'll update the higher voltages.
LOL the multipliers should be fine except the ridiculous 2.5 GHz typo that should never have been committed.
Click to expand...
Click to collapse
hmm your correct just took a quick gander at cm's tables. I say try increase the voltages accordingly and see if it makes a difference in readings

decimalman said:
Bizarre. The tables are all correct and should display correctly, but your app is probably expecting a slightly different format. What app are you using? I'll try to figure out what's going on.
Click to expand...
Click to collapse
I'm using set cpu. Thanks for looking into it.
Sent from my SGH-T999 using xda app-developers app

darjama said:
I'm using set cpu. Thanks for looking into it.
Sent from my SGH-T999 using xda app-developers app
Click to expand...
Click to collapse
I'm guessing this was an oversight on my part. I don't actually have the app, but I'm testing a bunch of fixes for a handful of different apps now. I'll push a test build (hopefully) later today that should get Voltage Control, Kernel Tuner, and maybe even SetCPU all working properly.

darjama said:
I'm using set cpu. Thanks for looking into it.
Sent from my SGH-T999 using xda app-developers app
Click to expand...
Click to collapse
New test build should get SetCPU working properly. If you get a chance, will you try flashing this test build and letting me know if it works for you?

decimalman said:
New test build should get SetCPU working properly. If you get a chance, will you try flashing this test build and letting me know if it works for you?
Click to expand...
Click to collapse
That seemed to fix it, thanks!
Sent from my SGH-T999 using xda app-developers app

darjama said:
That seemed to fix it, thanks!
Sent from my SGH-T999 using xda app-developers app
Click to expand...
Click to collapse
Great! If I don't run into any problems with the changes I made, I'll merge everything and it'll be in the next release.

robertd0619 said:
You download the att one. Works for tmo.
Sent from my SGH-T999 using Tapatalk 2
Click to expand...
Click to collapse
I figured as much. But was not 100% thanks
Sent from my Wicked fast SGS3!

[GUIDE] Custom Kernels: A Guide on What you Need to Know

I was searching for info about MPDecision and stumbled upon this..it's a very good read specially for beginner and those that want to know more about kernel specifics and how they work..this was written back in 2012:
---What IS a kernel?---
The ELI5 answer: "An analogy: the Kernel is like the Engine, Electrical system and the Transmission to a car. The Library, Framework and the Apps [AKA ROM] are the body frame and the rest of the Car." - faux123
In other words, the kernel is the software that controls the hardware at a very low level.
---The Stock Kernel---
The "stock" kernel is the kernel that comes with your Nexus 4 out of the box. It's compiled directly from Google's kernel source code and shipped on your device with zero modifications. A custom kernel, on the other hand, compiles the stock kernel source and adds various modifications to that code.
What are those modifications that kernel devs employ?
To understand what they mean, you need to understand the features of the stock kernel first!
What are the stock kernel parameters?
CPU min frequency: 384 MHz
CPU max frequency: 1512 MHz
Governor: Ondemand
I/O Scheduler: CFQ
What does each parameter represent?
CPU frequency: you can simply think of this as the "speed" the CPU is running at
Governor: regulates the CPU frequency based on many different parameters such as load and time-in-state. Here is an excellent list of many of the most common CPU governors and how each works. Note that you will only see a couple of the CPU governors on this list in whatever kernel you use. Ondemand and Interactive are by far the most widely used, and are the ones you should look at.
I/O Scheduler: handles how the system makes disk access; Please refer to the previous linked thread and scroll down to the 4th post for a detailed list.
What else do you need to know?
--PowerHAL--
PowerHAL is what makes Project Butter. The powerHAL is a ROM component that tells the kernel to BOOST the CPU frequency to higher values in response to UI inputs. The higher CPU frequencies can better respond to UI demands so the overall experience is smoother than without. - faux123
--mpdecision--
All Qualcomm based phones have Qualcomm prorprietary userspace binary called "mpdecision" aka m(ake)p(oor)decision. Instead of letting the kernel itself to decide what frequencies and how many cores to run, this "mpdecsion" binary polls the kernel run queue statistics and decides for the whole system the "optimal" frequency and the "optimal" number of cores to use. The concept is fine, except the decision making is done in userspace and it's 100% closed source so there's no way to tweak it and there's a latency (because all userspace binaries needs to "poll" the kernel for the latest information which is slightly delayed). - faux123
ELI5: mpdecision is a proprietary Qualcomm daemon that makes calls to the SoC (the entire chip your phone uses) to manage the cores. The OS (PowerHAL) makes a request to mpdecision and then mpdecision makes a request to the first two cores to ramp them up. - _motley
Why do kernel devs mess with these?
In practice, the PowerHAL ramping up trick successfully got rid of a lot of the UI lag since Android 4.1. However, this comes at the cost of battery life (and heat generation!) The reason for this is because the system ramps up its CPU on every touch input, rather than waiting for the kernel to calculate the load and ramp up accordingly. On the Nexus 4, when the PowerHAL makes a call to mpdecision it locks the minimum CPU to 1026 MHz upon touch input for the first two cores. While this DOES give you the buttery-smoothness you would expect, it's a bit overly aggressive. This is part of the reason why stock kernel tends to heat up your phone when you play around with it a lot.
---Custom Kernels---
What changes should I look out for?
--mpdecision--
Many kernel devs don't like Qualcomm's implementation, so they work around or get rid of it. Franco, Faux, Bricked, Matr1x, Motley, and Trinity have gotten rid of it/used their own implementations. Harsh and IntersectRaven's leave it intact. Every kernel dev implements things in their own way, and the only way to tell which is better for you is to try each one. This is by far the biggest change any kernel dev can make, as it completely alters how the system handles hotplugging and CPU scaling. In general, you'll find kernels without mpdecision running cooler, with greater battery life, but with a little more lag (made up for by other tweaks).
--thermald--
A binary that controls how to throttle your CPU based on CPU and battery temperatures. You can find the config file in /system/etc/thermald.conf. Stock configs lead to aggressive thermal throttling (battery temp. at 36 degrees C for example, which is easily achieved). You can look into the file and see the various thresholds and actions that the system takes to lower the temperature of the CPU and battery, but it isn't really necessary. Just know that some kernel devs may have changed this in order to allow your phone to run at higher frequencies for an extended period of time, or to further make your phone run cooler.
--Underclocking--
Quite straightforward, by limiting the max frequency your CPU can use, you use less power (higher frequency results in more power dissipated by the CPU).
P = C(V^2)f where C is capacitance, V is the voltage, and f is the current frequency
..gives you an idea of how underclocking (and undervolting) uses less power.
--Undervolting--
This is all the rage today, with many users trying to get as low as possible stable voltage. It's arguable how much undervolting saves battery life, but there's no doubt it reduces heat dissipated from the CPU (see: the above formula). Your CPU is located on the top half of your phone, which is likely where you've felt the heat before. How much your chip can successfully undervolt depends on what type of binned CPU you have. If you want to undervolt, I recommend checking if the voltages you set are stable by running the StabilityTest app and doing the Scaling Stability Test. The frequencies' voltages definitely don't scale linearly, so don't assume that doing global undervolts will be the best you can do. You'll have to apply voltages one by one if you truly want the lowest your chip can possible handle.
--Overclocking/overvolting--
Bricked, Trinity, and Motley's kernel implement this, because it CAN be dangerous. Overclocking usually requires overvolting the processor (so the overclock is stable) but overvolting carries with it the risk of bricking your phone by frying the CPU. Know that doing this has some risks before you try it. Some kernels like Matr1x and Faux's also allow for the GPU to be overclocked if games run a little slowly for you.
--Hotplugging--
Hotplugging is where the individual cores on your phone switch on/off depending on the load on the CPU. The advantage of hotplugging is a reduction in power used because the cores will only turn on when needed. Kernels that use the auto_hotplug binary by Thalamus (that would be Matr1x, Motley, Trinity, Bricked at the moment) allow you to fine tune the enabling and disabling thresholds. These parameters are generally for advanced users only as they require you to write scripts to control them.
--Color Control--
Gives you the ability to change color multipliers and gamma settings to calibrate your display. If you feel your display is too yellow, or you miss the previous feel of your previous phone, then you can mess around with this to get better color reproduction. You can find some user examples here to give you a good idea of what can be done. Gamma control currently requires either Faux's control app or for certain kernels you can use scripts to control them.
--Wakelock reduction--
Some kernels have reduced the msm_hsic_host wakelock duration so your phone enters deep sleep more often. How much improvement this makes is debatable, and whether or not this wakelock is even an issue is also debatable.
--Kernel modules--
Some kernels make modifications to the low-level drivers that interact with the components of your phone. An explanation of what is commonly touched can be found here. You don't really have to worry about this, just know that something is being improved when a kernel dev mentions it.
---Installing a Custom Kernel---
Just flash the zip in your recovery of choice. No need for wiping cache or anything. However, one thing to note that might save you some headache in the future is: what exactly are you flashing? When you flash a kernel, you are not just flashing the kernel, you are writing to the entire boot partition. The boot partition is made up of the kernel AND the ramdisk (the ramdisk is an image that the kernel mounts read-only at boot, it is basically used by the kernel to mount the rest of the system images). Some kernel devs pack their own ramdisk into their boot.img that you are flashing, so when you try to flash a DIFFERENT kernel, you end up in a bootloop. (An example: flash Franco kernel --> flash Faux kernel on top = bootloop.) To solve this you need to reset the ramdisk by flashing a stock reset kernel with the stock ramdisk.
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all content taken from [URL="http://www.reddit.com/r/nexus4/related/158t1i/custom_kernels_a_guide_on_what_you_need_to_know/"]a reddit post i found which was originally written [/URL]by reddit user IAmAN00bie